1. Field of Invention
The present invention relates to inverter-type electronic ballasts for gas discharge lamps, particularly of the type wherein a gas discharge lamp is connected with the inverter's output by way of a series-excited parallel-loaded resonant L-C circuit.
2. Description of Prior Art
Inverter-type electronic ballasts for gas discharge lamps of the type wherein the inverter output is connected with the gas discharge lamp by way of a series-excited parallel-loaded resonant L-C circuit are fundamentally cost-effective and energy-efficient. Such ballasts are described in prior art, such as in U.S. Pat. Nos. 4,461,980, 4,581,562 and 4,663,571 to Nilssen.
However, a very basic problem associated with such series-resonance-loaded inverter-type ballasts is that of the likelyhood of self-destruction in the event that the lamp is removed or otherwise fails to constitute a proper load on the series-resonant L-C circuit.
The prior art has dealt with that problem in various ways; and the issue now is basically that of finding a still more cost-effective way of so doing.